Role of ZnCl2 in the Uptake and Translocation of Cd to Different Parts of Wheat Plant and Risk Assessments for Cow and Human

Abstract

ABSTRACT In this study, we assessed the effect of zinc (Zn) when present in form of zinc chloride (ZnCl2) on translocation and accumulation of cadmium (Cd) in different parts of wheat plants (Triticum aestivum). Along with that, health risks to organisms of higher trophic levels (cows and humans) that consume these polluted wheat plants were also calculated. For the experiments, the soil was spiked with CdCl2 at rate of 3, 6, 12, 24, and 48 mg Cd kg−1 soil and ZnCl2 at a rate of 50, 100, 200, and 300 mg Zn kg−1 soil. In the combination treatment, all Cd concentrations used in single exposure were mixed in the soil that spiked with 200 mg kg−1 of Zn. According to the data, concentration of Zn and Cd in all parts of wheat plants increase with the increase of their concentration in the soil. However, soil application of Zn reduced Cd concentration in all parts of wheat plants (approximately two-fold in root and shoot, and more than 13-fold in the grains). The highest bioaccumulation of both metals was recorded in the roots and least in grains and leaves. The translocation factor also showed that roots store most of the metals and did not translocate them to the grains. The data showed that Zn application in the soil did not decrease ecological risk factor. However, daily intake metal (DIM) and health risk index (HRI) of cows showed that the Cd intake was higher than the permissible limit, but this quantity was not a health risk for cows. In humans, DIM values were higher than the permissible limit and caused severe health risk. However, a two-fold decrease in health risk of human due to Cd was recorded in the presence of Zn. This study revealed that ZnCl2 can be used to suppress the Cd uptake in wheat even at high pollution levels. It may decrease the risk of toxicity to higher tropic levels that consume different parts of wheat plants. In future further investigation about the role of ZnCl2 in the mitigation of other metals phytotoxicity is required to use it in agroecosystem.